This invention relates to sonar receivers and more particularly to receivers which are operated in parallel to provide outputs at a low false alarm rate which are processed by a computer using an algorithm which selects for presentation on a display only those signals which have a high probability of originating by a reflection of the transmitted signal from a reflecting object and not from noise or reverberation.
In the prior art, sonar signals from targets have been detected by using a receiver in conjunction with an operator wherein signals observed on a display are determined to be reflected signals from objects as distinguished from signal produced by reverberation or noise produced by the ocean or by the ship on which the sonar is being carried.
In order to reduce the dependence upon visual observation of the display by an operator for the detection of reflecting objects, it is desired to provide an active receiver which will provide a presentation of reflecting objects with high probability of detection while at the same time providing a presentation on the display from other than a reflecting object with low probability.
Current sonar practice is to display ra data (i.e. a substantial amount of clutter or random events from other than a reflecting object) and require the operator to decide if a reflecting object is present. It is an object of this invention to provide a system employing an algorithm which provides a totally new approach to the detection process in that only geographically consistent or target events from reflecting objects are displayed. Random or clutter events are not displayed, so true clutter-free operation is achieved.